Gamma-hydoxybutyrate (GHB) is a compound with a mixed reputation. On one hand it has been used quite successfully to treat persons suffering from narcolepsy and appears to be promising in the treatment of alcohol and opiate withdrawal. Furthermore it has been investigated as a treatment for schizophrenia, cocaine abuse, Parkinson's disease and night eating syndrome. On the other hand, GHB has been abused, presumably for its' psychoactive effects, with disastrous consequences including the development of a severe withdrawal syndrome, coma and even death. GHB has also been used to facilitate the commission of sexual assaults by surreptitiously providing it to the victim. Several investigators have suggested that GHB is a reinforcer with abuse potential while others have suggested exactly the opposite. Despite this wide-ranging history, the behavioral pharmacology of GHB has not been thoroughly examined. We are proposing a rigorous, inpatient double blind, placebo controlled, experimental procedure for assessing the physiological consequences, subjective properties, relative reinforcing potential, direct effects and pharmacokinetics of GHB in a group of regular GHB users. Furthermore, we are proposing to assess the degree to which GHB will be self-administered by volunteers. We believe that the successful completion of the proposed study will provide us with much needed data about the human behavioral pharmacological profile of GHB in the GHB user. We believe the data collected in the proposed study will be useful in developing effective treatments for those who have overdosed on GHB, for those who are in withdrawal from GHB, and for those who are attempting to quit using GHB. Furthermore, it is our belief that securing a fuller understanding of this interesting compound may help explain why it has come to be abused by certain individuals. This last point may be of particular importance as it is likely that other drugs, with profiles similar to that of GHB, will enter the "Club Drug" milieu in the future and we may be able to inform policy surrounding these future agents based on a fuller understanding of GHB.